“STEPHEN Tagg says he acts like an eight year-old most of the time anyway, so Horrid Henry isn’t a hard part to play. But don’t be fooled.

Horrid Henry is no ordinary boy, and playing him three times a day takes stamina.

But Stephen, right, knew exactly what he was taking on when he auditioned for the part, because when he isn’t acting, he runs a stage school for children in London.

For those of you who have missed the Horrid Henry phenomenon, he’s the hugely successful character created by Francesca Simons, and has a brother called Perfect Peter.

And whether you’ve read it or not, everyone can relate to him. Horrid Henry represents the devil in all children and his hilarious exploits are always uncomfortably spot-on.

Which is how Stephen likes to play the part.

“Horrid Henry is very easy to play in some ways, he says.

“You just have to think back to what it was like to be eight or 10 and relive it. You also have to throw away any insecurities you have as an adult to play this role and not care about what other people think.

“Because as an eight year-old you do not have preconceptions, you live for the moment and it’s all about what you can do and have now.

“So of course Henry is horrid, but he’s also very intuitive and has a great imagination, but everything has got to be about him and everything he does is about himself,” Stephen explains.

“So if there’s is a moral, it’s that life’s not fair because you can’t have ice cream if you don’t eat your broccoli, and it’s an adult’s world so he can’t be a dinosaur or go to the moon.”

Add to this the energy of an eight year-old and you’ve got the whole exhausting package.

“Yes, it’s quite a physical part,” Stephen admits.

“Because eight year-olds don’t think twice about running around for hours,” he laughs.

Stephen does, however, and after three shows a day, is happier tucked up in bed than out on the town with the rest of the cast.

“It’s really good fun, but you need stamina and I’ve got 20 years on Henry.”

So was Stephen a Horrid Henry or Perfect Peter then when he was young?

“I wasn’t naughty,” he insists.

“I had a great imagination when I was a kid, and neither me nor my younger sister was Horrid Henry or Perfect Peter.

“We were more like Charlie and Lola, because we were close when we were growing up and still are.

“But Francesca Simons has always said that Horrid Henry and Perfect Peter are the two extremes that you find in every child, the good and the bad.

“And Horrid Henry doesn’t always get away with it. Sometimes he gets away with murder and other times he ends up with egg on his face. But he’s not an evil person.”

Horrid Henry is at the Oxford Playhouse from Wednesday. Box office on 01865 305305.